According to scientists at the University of California in Irvine, a variant of the dopamine-receptor gene may be associated with longevity.
Their findings, published in the Journal of Neuroscience, show that the genetic variant called the dopamine receptor 4 (DRD4) 7-repeat allele, or DRD4 7R allele for short, appears in significantly higher rates in people more than 90 years old.
DRD4 7R allele is part of the dopamine system, which facilitates the transmission of signals among neurons and plays a major role in the brain network responsible for attention and reward-driven learning. The DRD4 7R allele blunts dopamine signaling, which enhances individuals’ reactivity to their environment.
Prof Robert Moyz of the University of California’s College of Medicine, senior author of the study, said: “people who carry this variant gene seem to be more motivated to pursue social, intellectual and physical activities. The variant is also linked to attention-deficit/hyperactivity disorder and addictive and risky behaviors.”
“While the genetic variant may not directly influence longevity,” Prof Moyzis said, “it is associated with personality traits that have been shown to be important for living a longer, healthier life. It’s been well documented that the more you’re involved with social and physical activities, the more likely you’ll live longer. It could be as simple as that.”
Numerous studies, including a number from the 90+ Study, have confirmed that being active is important for successful aging, and it may deter the advancement of neurodegenerative diseases, such as Alzheimer’s.
Prior study indicated that this ‘longevity allele’ was selected for during the nomadic out-of-Africa human exodus more than 30,000 years ago.
In the current study, the scientists analyzed genetic samples from 310 participants in the 90+ Study. This population had a 66 per cent increase in individuals carrying the variant relative to a control group of 2,902 people between the ages of 7 and 45. The presence of the variant also was strongly correlated with higher levels of physical activity.
Next, the team found that mice without DRD4 7R allele had a 7 per cent to 9.7 per cent decrease in lifespan compared with those possessing the gene, even when raised in an enriched environment.
“While it’s evident that the variant can contribute to longevity,” Prof Moyzis said, “further studies must take place to identify any immediate clinical benefits from the research. However, it is clear that individuals with this gene variant are already more likely to be responding to the well-known medical adage to get more physical activity.”
Bibliographic information: Grady DL et al. 2013. DRD4 Genotype Predicts Longevity in Mouse and Human. The Journal of Neuroscience, 33 (1): 286-291; doi: 10.1523/JNEUROSCI.3515-12.2013